1. Field of the Invention
The present invention relates to a pixel structure, and, more particularly, to the pixel structure and a fabrication method manufacturing the same utilizing metallic oxides.
2. Description of Related Art
Please refer to FIGS. 1A and 1B, which are conventional pixel structures of thin film transistors.
The thin film transistor (TFT) can be categorized into the following two forms: a bottom-gate structure thin film transistor 1a and a top-gate structure thin film transistor 2a. 
As shown in FIG. 1A, a pixel 1 is formed at a substrate 11, which can be separated into a thin film transistor region 10a and a pixel electrode region 10b. The bottom-gate structure thin film transistor 1a is formed at the thin film transistor region 10a. A gate conduction layer 12a, a gate insulation layer 13, a channel layer 14, source and drain conduction layers 16a and 16b, a protection layer 17, and a pixel electrode layer 18 are disposed sequentially in order to form the bottom-gate thin film transistor 1a. The pixel electrode layer 18 connects with the drain conduction layer 16b through the via hole 19. The source and drain conduction layers 16a and 16b contact to the channel layer 14 through the heavily doping semiconductor layer 15 for reducing the contact resistance between the source and drain conduction layers 16a and 16b and the channel layer 14.
The storage capacitor 1b is formed at the pixel electrode region 10b. The electrode layer 12b and the pixel electrode layer 18 serve as an upper electrode and a lower electrode of the storage capacitor 1b, respectively, and the gate insulation layer 13 and the protection layer 17 serve as an insulation layer of the storage capacitor 1b. The electrode layer 12b and the gate conduction layer 12a are formed at the same time but are separated from each other.
The gate conduction layers 12a and 12b, and the source and drain conduction layers 16a and 16b are usually made from opaque and conductive metal materials, such as gold, silver, titanium, aluminum, and compound metal thereof. The channel layer 14 is usually made from amorphous silicon semiconductor. The pixel electrode layer 18 is usually made from translucent and conductive metallic oxides, such as ITO, IZO, IGZO, etc.
Another pixel 2 of FIG. 1B has the top-gate structure thin film transistor 2a at the thin film transistor region 10a, and has a storage capacitor 2b at the pixel electrode region 10b. The top-gate structure thin film transistor 2a is formed by sequentially disposing the separated source and drain conduction layers 16a and 16b, the channel layer 14, the gate insulation layer 13, the gate conduction layer 12a, the protection layer 17, and the pixel electrode layer 18. Alternatively, another top-gate structure thin film transistor (not shown) may include the channel layer 14 formed upon the substrate 11 while the separated source and drain conduction layers 16a and 16b formed upon the channel layer 14.
The storage capacitor 2b is formed at the pixel electrode region 10b. The electrode layer 16c and the pixel electrode layer 18 serve as the upper electrode and the lower electrode of the storage capacitor, and the gate insulation layer 13 and the protection layer 17 serve as the insulation layer of the storage capacitor 2b. The electrode layer 16c and source and drain conduction layers 16a and 16b, all of which are separated from each other, are formed at the same time.
As described above, the bottom-gate structure thin film transistor 1a and the top-gate thin film transistor 2a are only different in the sequence of disposing each of the aforementioned layers.
The conventional gate conduction layer 12a and source and drain conduction layers 16a and 16b of the thin film transistors 1a and 1b are made from opaque and conductive metal materials. Since the electrode layers 12b and 16c of the storage capacitors 1a and 1b may block the light from passing through, at the time of manufacturing light-penetrating display devices with the thin film transistors an aperture ratio (AR) may stay at 60%. Thus, such light-penetrating display devices at most provide only 60% of the light supplied by a backlight module. With a color filter, a polarizer, and other components of the display device absorbing the light, these display devices usually end up with being capable of providing only 10% of the light from the backlight module.
For increasing a luminance of the light-penetrating display device, many pixel designs have been prepared for increasing the AR of the pixel structure. But the luminance of the existing light-penetrating display devices still remains unsatisfactory without having the backlight module with greater luminance incorporated or increasing the cost of manufacturing the same.